Adding screw terminals to pre-screw terminal Headways

[jonnybump]

Following on from my recent post, I've discovered it's nigh on impossible to source the pre-screw terminal 38120 headway cells that are already fitted in my battery pack. I like the idea of using the screw type cells as I assume they'll be much easier to maintain than spot welded types if there are problems in the future.
If it turns out I need to order two new cells (they're being tested at the moment) they'll be the screw type. Is it possible to add screw terminals to every other cell in the pack and for the pack to be rebuilt using screw connectors? I found a post suggesting someone was going to do this but couldn't find out if he was successful.

Thanks
Jon

 

[e-beach]

.....Is it possible to add screw terminals to every other cell in the pack and for the pack to be rebuilt using screw connectors?

I am not understanding what you are trying to say....If you only add connectors to every other Headway cell, how are you going to connect them. The headway cells you referenced have screw connectors. How else are you going to connect them?

What do you mean rebuilt using screw connectors?"

 

[jonnybump]

Hi, my battery pack consists of 32 spot welded 38120 cells. They don't have the screw terminals. Two cells may need replacing and I can only buy the new screw terminal cells.
I was wondering if it would be possible to add screw terminals to all the other 30 cells in the pack to make it easier to swap out a cell if it goes bad in the future?

Thanks
Jon

 

[amberwolf]

Headways have had screw (and/or bolt) terminals for a long time (years), so exactly how old are your cells?

If you post pics of your cells and pack construction, someone might have ideas on how you can fit the new ones in there and connect them.

As for adding screw terminals to your old ones, well, without any pics of what you already have there, I can only guess that you'd basically have to glue screw heads onto the cell ends (or rather, the spot-welded tabs), with the threaded rod end pointed out away from the cell end, then add ring terminals to wires that are then soldered or otherwise fastened to the spot-welded tabs. Then slide the ring terminals over the screws, along with ring terminals or busbars to the next cell in series, etc.

You'd want to add some sort of insulated support structure to hold the screws themselves in place relative to each cell, so that when the glue eventually breaks down from heat, vibration, aging, etc., the screws dont' fall into each other and create a short.

(that isn't really needed for the cells with screws built into them, but if you're adding them on, then that means they can come off under the right conditions and that's when bad stuff can happen).


I would recommend leaving the existing tabs that are connecting the existing cells, until you actually have to remove a cell for some reason.

 

[parabellum]

https://endless-sphere.com/forums/viewtopic.php?f=2&t=2633&p=91045#p83791

 

[999zip999]

Yes you can. Just be careful not short to the tab material to the case on the positive side. I would use a gasket so the negative case doesn't short with the positive screw. The whole case is negative just the screw is positive. The nipple. This is the danger zone. Hope you understand.
Its like most batteries. Plus give us the pics.

 

[mark.curry3]

I have a pack with the same issue. 3 of the 38120 cells are bad. I have been looking for these flat end headway cells and found some at evassemble.com. I am currently trying to get them to spot weld the three so I can replace them in the pack. The biggest issue is getting these connected as I do not have access to a spot welder. If anyone knows of a fix or other source, I would appreciate any help.